1. Field
Exemplary embodiments disclosed herein relate to memory devices which stably operate and methods of forming and operating the same.
2. Description of the Related Art
Nonvolatile memory devices are memory devices that may maintain stored data when a power supply is interrupted. A flash memory device is a typical nonvolatile memory device.
A flash memory device includes a floating gate and may electrically program and erase data. Data programming and erasing operations may be performed by injecting charges into or emitting charges from an electrically isolated floating gate. Injection of charges and emission of charges may be performed by a hot carrier injection method or a Fowler-Nordheim tunneling method. Generally, an operating voltage, e.g., a programming voltage or an erasing voltage, may be applied to a control gate electrode. Charges may be injected into a floating gate or emitted from a floating gate by a voltage induced in the floating gate by the operating voltage. As a design rule of a semiconductor device is reduced, electrical problems, e.g., leakage, may arise during programming operations.